The present invention relates to a virus capable of inducing lymphadenopathies (hereinafter "LAS") and acquired immuno-depressive syndromes (hereinafter "AIDS"), to antigens of this virus, particularly in a purified form, and to a process for producing these antigens, particularly antigens of the envelope of this virus. The invention also relates to polypeptides, whether glycosylated or not, produced by the virus and to DNA sequences which code for such polypeptides. The invention further relates to cloned DNA sequences hybridizable to genomic RNA and DNA of the lymphadenopathy associated virus (hereinafter "LAV") of this invention and to processes for their preparation and their use. The invention still further relates to a stable probe including a DNA sequence which can be used for the detection of the LAV virus of this invention or related viruses or DNA proviruses in any medium, particularly biological, and in samples containing any of them.
An important genetic polymorphism has been recognized for the human retrovirus which is the cause of AIDS and other diseases like LAS, AIDS-related complex (hereinafter "ARC") and probably some encephalopathies (for review, see Weiss, 1984). Indeed all of the isolates, analyzed until now, have had distinct restriction maps, even those recovered at the same place and time [Benn et al., 1985]. Identical restriction maps have only been observed for the first two isolates which were designated LAV [Alizon et al., 1984] and human T-cell lymphotropic virus type 3 (hereinafter "HTLV-3") [Hahn et al., 1984] and which appear to be exceptions. The genetic polymorphism of the AIDS virus was better assessed after the determination of the complete nucleotide sequence of LAV [Wain-Hobson et al., 1985], HTLV-3 [Ratner et al., 1985; Muesing et al., 1985] and a third isolate designated AIDS-associated retrovirus (herein-after "ARV2") [Sanchez-Pescador et al., 1985]. In particular, it appeared that, besides the nucleic acid variations responsible for the restriction map polymorphism, isolates could differ significantly at the protein level, especially in the envelope (up to 13% of difference between ARV and LAV), by both amino acids substitutions and reciprocal insertions-deletions [Rabson and Martin, 1985].
Nevertheless, such differences did not go so far as to destroy the immunological similarity of such isolates as evidenced by the capabilities of their similar proteins, (e.g., core proteins of similar nature, such as the p25 proteins, or similar envelope glycoproteins, such as the 110-120 kD glycoproteins) to immunologically cross-react. Accordingly, the proteins of any of said LAV viruses can be used for the in vitro detection of antibodies induced in vivo and present in biological fluids obtained from individuals infected with the other LAV variants. Therefore, these viruses are grouped together as a class of LAV viruses (herein-after "LAV-1 viruses").